MYDRIASIS
mydriasis
(noun) reflex pupillary dilation as a muscle pulls the iris outward; occurs in response to a decrease in light or certain drugs
Source: WordNet® 3.1
Etymology
Noun
mydriasis (plural mydriases)
(medicine) The condition of having abnormally large and dilated pupils due to disease or drugs, particularly stimulants such as (meth)amphetamines, cocaine, etc.
Antonyms
• miosis
Source: Wiktionary
My*dri"a*sis, n. Etym: [L., fr. Gr. (Physiol. & Med.)
Definition: A long-continued or excessive dilatation of the pupil of the
eye.
Source: Webster’s Unabridged Dictionary 1913 Edition